http://www.mozilla.org/projects/thunderbird/specs/junkmail/junkmail.html
add a new default pref for forcing HTML junk mail to be displayed using sanitized HTML.
Defaults to true and is controlled via the Settings tab in the junk mail controls dialog.
git-svn-id: svn://10.0.0.236/trunk@144339 18797224-902f-48f8-a5cc-f745e15eee43